Cats and Dogs
by FredMischiefmanagedGeorge
Summary: Cassiopeia, in pre-Crookshanks form, finds a friend in a person she had not known existed. His name was Sirius Black. And he was chasing her. Written for the Quidditch League Fanfiction Competition-Round 13 Sirius/Crookshanks(in other words slight Oc)


**A.N I find this to be a very long one shot. I'm sorry about that, honestly. But I'm tired, so there's my excuse :P**

**Team: Tutshill Tornadoes**

**Position: Captain**

**Round: 13**

**Writing about: a pairing- Sirius/Crookshanks**

**Title: Cats and Dogs**

**Words: 2983**

**For those of you innocent people who stumble upon this one-shot and are unaware of my speaking of Quidditch, teams and nonsense, it is alright! This is for a sort of contest on a forum and nothing that you aren't allowed to read, so enjoy!**

**Disclaimer: Characters and all other recognizable written words such as 'incendio' belong to J.K Rowling.**

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><p>Years ago Crookshanks had been much different. In fact, Crookshanks had been a girl. And Crookshanks had also been fine friends with the marauders. As well, Crookshanks name was not Crookshanks. Her name was Cassiopeia, so named after the constellation.<p>

Cassiopeia was a girl who had been raised in a pure blood family, full of supremests as viewed by certain families in the magical world. Cassiopeia had grown up in their views, but her instinct was to see both sides. It was just how she was. Cassiopeia loved her family, and would protect them to the end, but she hated the unfairness of it all.

"HUFFLEPUFF!" the hat had yelled.

There were a few mutters, but Cassiopeia ignored them. She walked down the steps towards the Hufflepuff table, her ginger hair bouncing behind her. Cassiopeia sat alone, away from the others. Her amber coloured eyes, looked down.

She had not been among other children her age before, and was rather shy. She ignored all of them, which caused them to think she was an ignorant person full of condescension. Cassiopeia did not know this, however, and thought they were kindly leaving her to her own devices so as to not make her upset.

Cassiopeia was confused as people ignored her when she picked up her courage to ask a question. Weren't they supposed to be nice? She hadn't turned in homework on time due to them. It was clear the Hufflepuffs weren't as welcoming as they were said to be.

For the next four years, Cassiopeia was alone. She walked the halls alone, and ate alone. Luckily, Cassiopeia had found the kitchen within the first two years, which allowed her to eat alone without looking too awkward.

Her parents had accepted her, saying that at least she wasn't in Gryffindor, and that was enough with them. Yet she knew they blamed themselves for her getting in Hufflepuff. They believed they had not raised a perfect Slytherin pure blood.

"Every person has flaws." her father had said to comfort her.

Cassiopeia knew it was more of a comfort to him. Why did she have the flaw of being different, when other pure bloods were in Slytherin. Why were they so perfect?

She hated her house. Being ignored was more than hurtful, it was painful. Cassiopeia was invisible to the students of Hogwarts, even though she had done nothing wrong.

"Your Richelieu, aren't you?" a voice asked.

Cassiopeia jumped, nearly spinning her cocoa, and looked around wildly. Her eyes met those of a boy with black hair nearly down to the neck, and striking grey eyes. She stared at him.

"Well, are you?" he asked, impatiently.

When she did not respond, he rolled his eyes at Cassiopeia. Then, he plopped down in front of her.

"You're a Richelieu in Hufflepuff." he tutted. "Ooh, I bet your parents aren't proud."

"Shut up." Cassiopeia whispered.

"What?" the boy asked. "Sorry, didn't hear you."

"Shut up." she repeated, in a much stronger voice.

"Will you look at that," the boy commented. "a Hufflepuff being 'mean', if only Prongs could see this now."

Where had she heard that word before? Cassiopeia shook the thought away. Right now, she was dealing with a _crétin_. Cassiopeia calmed herself down. Whenever she got angry, she began to speak french. It was a habit she had picked up from her mother when she shouted at the french elves.

"Hufflepuffs aren't nice." she muttered.

'_Red alert!_' her mind screamed. '_He is going to make a remark, and it'll set you off._'

Cassiopeia stood up quickly, said a quick thank you before leaving the rude boy behind. She had enough of interaction with people today.

oOo

'_Two stirs_' Cassiopeia thought to herself. '_Two stirs, and I'll be good, and done._'

Relief flooded through her when she finished. Her hair was frizzled, as she looked into the cauldron. It had taken nearly the whole of yesterday, and today to complete it. Hoping it would work well with her new experiment, she took a frog out of the box.

"It's alright, froggy." she said to the little creature.

The frog croaked at her in response. Cassiopeia sighed. She hated to do this to animals, but it was the only way to get to human trials.

She took a spoonful of the grey, and bubbly potion, and poured it into the frog's mouth before quickly setting it inside the plastic box she had.

"Now stay there," Cassiopeia told it.

Quickly, she packed up her instruments when a ghost flew up to her, screaming.

"Oh Cassiopeia! You won't believe what I've found! Those marauders have set a prank in the hallways! A bunch of cats are following Severus Snape around!"

Cassiopeia cocked her head to the side.

"Who are they, Myrtle?"

"Oh, poor you." Moaning Myrtle pitied. "They are only the heart-throbs of the castle! That Sirius Black, especially. That Severus Snape, however, can't be said to be on the same level. He has the attractiveness of a trout. A dead trout."

_Black_, that was a pure blood family, wasn't it? She was quite sure, but payed more attention to her studies than the families of the system.

"That's interesting." Cassiopeia said. "Well, I have to go-"

"What, you don't want me to be around, then?"

Cassiopeia kept in her sigh of annoyance.

"Not at all, Myrtle. You are a pleasure to have around." Cassiopeia told her. "I'll come see you again, maybe next week. My teachers are giving me a load of homework."

She quickly made her way out into the halls before the ghost could burst into tears. As she turned the corner, reorganizing the objects in hand, she bumped into someone. Correction: she crashed into someone. Falling on top of the person was not her plan. Especially falling on top of the boy from before.

Cassiopeia looked up quickly, watching as her plastic box fell...then opened at the top! She scrambled over to it, quickly closing the box. Cassiopeia looked inside it, and felt her heart thud against her chest. She hoped to Merlin the frog was still in their.

See, she had been brewing an invisibility potion. It had taken all summer to come up with the perfect equations, and ingredients. The potion had finally worked on the little frog, but she didn't know if it was still in there.

"_Aparecium _frog." Cassiopeia said, pointing her wand at the box.

The frog didn't appear. Cassiopeia began to panic. Then she heard the boy choking. She whirled around, suddenly angry. This was ALL his fault.

"You complete idiot! That was my subject! _Mon sujet d'essai!_ _Ses tous votre redire! (my test subject! It is all your fault!)_" she yelled in french.

Then Cassiopeia noticed something she had not before. A little green frog sat in the boy's mouth. Cassiopeia sighed in relief. The frog was not lost. The boy spat it out, and proceeded to wipe his tongue, while Cassiopeia picked up the frog, and cooed over it.

"You care about that frog, more than you do me?" the boy asked in disbelief.

Cassiopeia had nearly forgotten he was there. What an arrogant boy!

"He looks a whole lot prettier than you do." she said, in a rare fit of confidence.

Maybe it was because of her mind not being totally on the situation. Or it could be the fact that she was starting to be fueled up by anger for this boy.

"Well, I _am_ insulted." the boy exclaimed. "Are you not going to help me?"

"What? After you caused my stuff to go everywhere, and nearly swallowed my frog? No." Cassiopeia said.

"Fine, I can see how nice Hufflepuffs are." the boy remarked.

Cassiopeia rolled her eyes before waving her wand. This caused her possessions to fly slowly into her bag, which was over her shoulder. Cassiopeia held the frog in the plastic box at her side, before walking away.

"What? No apology?" Sirius called out.

Cassiopeia rolled her eyes once again.

oOo

It was her fifth year, and she was to take defense against the dark arts with the Gryffindors. Cassiopeia walked towards the classroom, adjusting her book bag strap upon her shoulder. She had never had a lot of classes with Gryffindor. The only one usually being Herbology, and any extracurriculars.

Cassiopeia had also not been in the Great Hall for ages, only going for the beginning of the year feast. Her dorm and classrooms were the only places where she really interacted with others the most.

So it was with absolute dread when she walked into the classroom, spotting the boy whom had irritated her twice last year. He was talking with his friends, while one of them stared off towards something. Cassiopeia neither cared, nor wanted to know.

She took her place at the front of the classroom. The professor introduced himself, this was the fifth DADA professor she had. There were murmurs of a curse on the position, and Cassiopeia was starting to believe it.

"Today I want to break right into the course, and step up to learning the patronus charm." their Professor told them. "Now, the study will be of what form it'll take. We will be going into study about it."

There were mutters throughout the classroom, while Cassiopeia bit her lip in thought. Her days at Hogwarts had not exactly been the best, nor had her days at home been any better. She had no friends, absolutely no friends besides the moaning ghost.

"Yes, exciting isn't it? Now I would like you to get into pairs to study, and practice together-"

There were scrapes of chairs as people left to get to their friends, glancing at the teacher warily, in case he would be choosing instead.

"Brilliant!" he exclaimed cheerfully. "Does anyone not have a partner?"

Cassiopeia let out a quiet sigh before raising her hand into the air.

"Excellent, miss…" the teacher gestured to Cassiopeia to answer.

"Richelieu." she answered.

"Alright, Miss Richelieu and Mr-?" the teacher gestured behind her.

"Potter." a familiar voice answered.

Cassiopeia found it rather hard to suppress a groan. With all the luck in the world, she was stuck with this boy! Why did the world hate her?

"Oi! That's my name!" another voice exclaimed. "He's Black, sir!"

"Okay, well, Mr. Black, and Miss Richelieu, I hope you find the pleasure working together."

Cassiopeia found her head in her hands. Soon enough, she felt an arm over her shoulder. What did he say his last name was? Black? Was he Sirius Black? Cassiopeia supposed he was rather good-looking, now that she thought about it.

No! She couldn't think about it! Sirius Black was an annoying toad. Not a frog, of course, she loved frogs.

"Please take your arm off of my shoulders, Black." Cassiopeia said, looking at him.

Sirius obliged, smirking all the while. Cassiopeia wanted to shoot a jelly legs jinx at him, one she had perfected, and wipe the smirk clean off of his face.

"Come on, princess." Sirius said. "We're supposed to study about the charm."

"Don't call me princess." she muttered, opening up the textbook.

Cassiopeia knew he was still smirking, even more so now. As she flipped to the page of the patronus', Sirius closed her book. Cassiopeia sent him an irritated look.

"What are you doing? You said we had to study about the charm!"

"Fortunately, I know a lot about the patronus charm." Sirius gloated.

"Oh really?" Cassiopeia smirked. "What's the corporal patronus look like?"

"It summons your animal guardian, or the animal that most represents you. It is the colour of silver."

"What is the effect?"

"It brings out your most positive emotions, which is why it helps around dementors, and can help fend them off."

"How much do-"

"Face it, princess. I know a lot about it, and I can even cast it."

"Really?" Cassiopeia challenged.

Sirius raised his eyebrows, and smirked. He then waved his wand, causing a bright silver dog to appear. The classroom watched in awe as the dog leapt around before heading back to Sirius and disappearing. Sirius looked back at her, and grinned when he saw her mouth was open. Aware of this, Cassiopeia closed her mouth quickly, looking back at her textbook uncomfortably.

"I'm not impressed." she said.

"Right, princess. Aren't you glad you are with me?" Sirius laughed.

_Hardly_, Cassiopeia thought, but couldn't suppress the small smile.

oOo

"Just think of-"

"I know, shut up!" Cassiopeia yelled, irritatedly.

Sirius was pushing her to find a memory to make a corporal patronus. Cassiopeia thought she had a few, such as her first time flying a broom. Yet the broom flying wasn't entirely special to her. Nothing seemed to be.

Cassiopeia and Sirius were on more friendly terms now, having gotten to know each other. Cassiopeia could easily say he was her best friend. She didn't want to admit it, though.

"We'll continue this tomorrow, I have some things to finish." Sirius said, glancing at his wristwatch.

"Alright." Cassiopeia said.

She couldn't help the wave of disappointment wash over her. Cassiopeia started to pack up her books, when she realized Sirius had not left yet. She looked up slowly to meet his eyes. Cassiopeia felt a fuzzy feeling overcome her.

Sirius looked like he wanted to say something, but seeming to think better of it, shook his head before smiling at her.

"Bye, princess."

Cassiopeia almost forgot to scowl at his nickname for her.

"Bye, dog."

She heard Sirius laugh as he left.

oOo

Cassiopeia made her way to the library, where she hoped to finish her essay in potions. Unfortunately, Sirius thought it would be the perfect time to practice the patronus charm.

"Sirius! I need to work!"

"And this is work, princess."

"It's not due until we will be presenting it in exams!"

"It might help you."

Cassiopeia glared at Sirius as he dragged her in the opposite direction of the library, and out onto the grounds. He then stopped her under a tree.

"Do you have your memory?" Sirius asked.

"No." Cassiopeia admitted, defeated. "I don't have any good memories. I'm going to fail my exam Sirius!"

"No you aren't." Sirius said. "Here, if you don't have any, we'll have to make some."

"How?" Cassiopeia frowned.

"Close your eyes." Sirius told her.

Cassiopeia did as he said. She heard Sirius walk around in front of her.

"You feel it, the breeze? The silence?"

"How would I feel silence?"

"Well, you broke it. So, shush."

"Fine, I feel it."

"Good. Now, do you feel relaxed?"

"I suppose." Cassiopeia replied.

Then she felt it. Sirius' lips on hers. To her surprise, it was the most magical feeling in the world. No spell, potion, or magical creature could make her feel this way. Warmth filled her.

His lips were only there for a few seconds before they left hers. Sirius whispered to her, and Cassiopeia could feel his breath on her lips.

"Don't open you eyes." he told her.

She felt something being pressed into her hand. Her wand.

"Now do the spell."

Cassiopeia hesitantly rose her wand into the air. She thought to to kiss she and Sirius had shared. Cassiopeia focused on the feelings she had felt.

"_Expecto Patronum_!" Cassiopeia said in a confident voice.

"Open your eyes." Sirius instructed her.

Cassiopeia slowly opened her eyes, and saw the animal before her. It was a silver cat, jumping around.

"_Expecto Patronum_." Sirius said.

His silver dog leapt out of his wand, and raced up to the cat. They touched noses before the dog started to chase the cat around. Cassiopeia laughed.

"You know," Sirius began, looking at Cassiopeia. "Dogs chase cats."

"They do." Cassiopeia nodded.

"And I've chased you since day one."

Cassiopeia stared at him with wide eyes.

"You mean, you fancied me ever since first year?"

"No," Sirius chuckled. "Truthfully, I didn't know you existed-"

"Charming." Cassiopeia remarked.

Sirius suddenly looked alarmed.

"I'm sorry! I-I didn't mean-"

Cassiopeia laughed.

"I know what you meant." she said, then seemed to become shy. "And if you want to know something, sometimes cats chase dogs too."

In the next few years, Sirius and Cassiopeia were in a relationship. Cassiopeia was engaged to Sirius after graduating. Sirius did not work, living off his uncle's riches he was given. He did, however, do missions for the order. Cassiopeia did her own personal work where she invented new spells, and potions. She knew it was dangerous, but loved her work. Their lives were as calm as it could be. Until the fateful day where James and Lily died. Sirius was taken to Azkaban, and Remus was gone. Peter was dead.

Cassiopeia lost all her friends she had made. She didn't understand what had happened with Sirius, fully.

The now twenty-one year old fell into depression from the loneliness. It began to affect her magic, causing a rogue spell from Cassiopeia's inventions to backfire on her. She was left in the form of a male cat. Wondering what had happened, and quite confused.

Cassiopeia had been taken in by the Magical Menagerie. She had tried to seek help from them by grabbing at them, and meowing constantly. It didn't seem to work. Plus, no one wanted her. She was an ugly tomcat with a squashed in face.

No one wanted her. Not until Hermione walked in with the boy whose parents she had later been friends with. There was no telling what the future would hold, but Cassiopeia-now Crookshanks, knew she would protect Harry to her very best.

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><p><strong>A.N It was either this, or a love potion. The love potion bit just wasn't speaking to me. I always write one version before rewriting the whole thing. So, here it is. I hope you enjoyed it, though I feel utterly horrible about it. The ending was rushed because I didn't think I would have enough space to write more. Plus, I had no idea what else to write.<strong>

**I have been listening to many different disney songs, plus Jason Walker. So if anything looks weird I might have been emotional with the music (including getting sidetracked!).**

**So Cheers!**

**Lupey**


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